The long-term objective of the research is to develop reagents that activate human gamma globin gene transcription in the adult for treatment of beta-thalassemia and sickle cell anemia. It is known that expression of the fetal gamma globin genes greatly ameliorates the effects of these diseases, however it is not known how the human gamma globin genes are normally suppressed (or expressed at very low levels) when the expression of the human gamma globin genes switches to that of the delta and beta globin genes. It could be the result of an absence of transcription factors required for gamma globin gene expression or the presence of active suppressors of gamma globin expression or both. The aim of this application is therefore twofold: the characterization of the stage specific factors that are required for gamma globin gene expression and/or the stage specific factors that suppress gamma globin gene expression. Two independent in vivo approaches will be used. One uses chromatin precipitation to directly purify and sequence the proteins bound to the gamma globin gene promoters in the fetal stage and adult stage. The other is a functional assay to obtain single chain antibodies that switch on the gamma globin genes in the adult stage.